The developmental origins hypothesis relates early exposures to endocrine disrupting chemicals (EDCs) to the development of chronic diseases, including metabolic syndrome, a condition affecting up to 25% of US adults and 30% of obese adolescents. Limited research in humans has considered the mechanisms by which exposures to EDCs mixtures interact with diet to alter maternal and child metabolic homeostasis, nor considered whether subsequent exposures during adolescence exacerbate risk of metabolic syndrome. Pilot human and animal data from our Formative CEHC: 'Perinatal exposures, epigenetics, child obesity and sexual maturation (P20 ESDI 8171/ RD834800, Pl: Peterson) suggest that the disruptive effects of representative maternal EDCs on metabolic and epigenetic markers may differ across sensitive periods of child development. Drawing on unparalleled institutional resources including the UM NIEHS Center of Excellence Epigenetics Laboratory (P30 ES017885) and the Michigan Nutrition and Obesity Research Center (MNORC, P30 DK089503), this project will test the hypothesis that EDC mixtures (BPA, phthalates, lead, cadmium) via epigenetic mechanisms induce oxidative stress (tyrosine oxidation products), disrupt metabolic homeostasis (free fatty acids, amino acids, Acyl-carnitine) and lead to changes in gene transcription and metabolic function. We further hypothesize that dietary macro- and micronutrient intake and dietary patterns during pregnancy and adolescence will modify the impact of EDC mixtures on these outcomes. Study participants include the Michigan Mother-Infant Pairs (MMIP) cohort (n=80) (extension of R01 ES017005, PI: Padmanabhan) and 400 children followed from pregnancy to 8-15 years of age through our 18-yr Early Life Exposures in Mexico to ENvironmental Toxicants (ELEMENT) collaboration with Mexico's Instituto Nacional de Salud Publica (INSP). Findings will: 1) provide proof of concept that EDC mixtures perturb metabolic homeostasis, 2) clarify the role of diet in amplifying or negating such effects, 3) illustrate the epigenetic and transcriptional changes involved and 4) inform the design of future interventions to modify metabolic consequences of EDC exposures both in utero and during the pubertal transition.